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    <title>Document</title>
    <script>
        var str = 'ewfycygegeqhjsdhhsss3773423879';
        // 问题：
        // 1.字符串长度
        console.log('1.字符串长度为 ' + str.length);
        // 2.取出下标位置为3,5,9的字符
        console.log('2.取出下标位置为3,5,9的字符分别为 ' + str[3] + str[5] + str[9]);
        // 3.查找字符'i' 'c' 'b'有无在字符串中
        var i = str.indexOf('i');
        if (i = -1) {
            console.log('i不在字符串中');
        } else {
            console.log('i在字符串中');
        }
        var c = str.indexOf('c');
        var b = str.indexOf('b');
    </script>
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